Charged particle beam device

Abstract

The present application provides a charged particle beam device capable of efficiently finding optimal parameters of the device in a short time. The charged particle beam device of the present application includes: an electron gun (1) that irradiates an electron beam (2) to a sample (10); an image processing section (901) that obtains an image of the sample (10) from a signal (12) generated from the sample (10) by the electron beam (2); a database (604) that stores a plurality of analysis values and measurement values in correspondence with each other with respect to a first parameter as an optical condition, a second parameter as a value related to a device performance, and a third parameter as information about a device structure; and a learner (605) that searches and finds the first parameter satisfying a target value of the second parameter from the database (604).

Description

TECHNICAL FIELD

[0001] The present application relates to a charged particle beam device that irradiates a sample with a charged particle beam, detects a signal including secondary electrons generated from the sample, and obtains an image. BACKGROUND

[0002] As a charged particle beam device that irradiates a sample with a charged particle beam, detects a signal (secondary electrons) secondarily generated from the sample, and obtains an image, there is a scanning electron microscope (hereinafter referred to as "SEM"). In particular, in a semiconductor wafer inspection device using an SEM, in order to observe the surface of a large-area semiconductor wafer, it is required to obtain an SEM image with high resolution while maintaining high throughput. In addition, as the miniaturization of semiconductor wafers progresses year by year, the requirements for improvement of measurement reproducibility of the SEM, reduction of measurement errors between devices, and the like are increasing. Hereinafter, the reduction of measurement errors between devices to obtain the same measurement results between devices is referred to as "matching".

[0003] In order to obtain an SEM image with high resolution, it is necessary to correctly set the optical conditions of the device when irradiating the wafer with an electron beam. The optical conditions are, for example, the acceleration voltage of the electron beam, the opening angle of the electron beam, the current value of the electron beam, and the voltage of each electrode. In order to match, it is necessary not only to make the optical conditions the same, but also to make the information obtained from the SEM image and the state of the electron beam the same between devices. The information obtained from the SEM image is, for example, the line profile and the length of the wafer. The information obtained from the SEM image differs depending on the shape of the wafer, the optical conditions and the configuration conditions of the device, and the like. The configuration conditions of the device are, for example, the shape of the lens, the position in the height direction of the lens, the position in the lateral direction of the lens, the tilt angle of the lens, and the flatness of the lens.

[0004] When matching is performed, the optical conditions and the configuration conditions of the device need to be considered, and the optical conditions are adjusted again in such a way that the measurement error between devices becomes below a threshold value decided in advance. In the adjustment work of the optical conditions, for each device to be matched, the worker needs to know the structure of the device, the interaction between each adjustment item, and the selection of the adjustment item is different depending on the insight of the worker. Furthermore, since a plurality of optical conditions are handled at the same time, the matching work takes a long time. Therefore, a device capable of performing the matching work in a short time is required.

[0005] Examples of existing charged particle beam devices are described in Patent Documents 1 and 2.

[0006] A charged particle beam device capable of performing condition setting with high precision is disclosed in Patent Literature 1. The charged particle beam device of Patent Literature 1 compares a calculated optical condition obtained by orbit calculation with an optical condition obtained by performing image adjustment on a resulting SEM image, and stores the optical condition if they are identical.

[0007] In Patent Literature 2, a charged particle beam device that reduces measurement size difference (mechanical difference) between devices is disclosed, and as a wafer used in correction for reducing mechanical difference, a sample using a polyhedral structure body in which a plurality of pyramid shapes (tetrapods) are arranged is described.

[0008] Prior Art Documents

[0009] Patent Literature

[0010] Patent Literature 1: Japanese Patent Application Laid-Open No. 2006-32202

[0011] Patent Literature 2: Japanese Patent Application Laid-Open No. 2007-187538 SUMMARY

[0012] Problems to be Solved by the Invention

[0013] In the charged particle beam device described in Patent Literature 1, parameters such as optical condition, configuration condition, and the like of the device are changed one by one to perform comparison until the optical condition obtained by analysis and the optical condition obtained by measurement are identical. However, since the number of combinations of parameters is large, in such prior art, there is a problem that it takes a long time to search for the identical optical condition.

[0014] An object of the present application is to provide a charged particle beam device capable of efficiently finding optimal parameters of a device in a short time.

[0015] Means for Solving the Problems

[0016] The charged particle beam device of the present application includes: an electron gun that irradiates an electron beam to a sample; an image processing section that obtains an image of the sample from a signal generated from the sample by the electron beam; a database that stores a plurality of analysis values and measurement values in correspondence with each other with respect to a first parameter that is an optical condition, a second parameter that is a value related to device performance, and a third parameter that is information about device structure; and a learner that searches and finds the first parameter that satisfies a target value of the second parameter from the database.

[0017] Effects of the Invention

[0018] According to the present application, it is possible to provide a charged particle beam device capable of efficiently finding optimal parameters of a device in a short time. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a view showing the structure of the charged particle beam device of Embodiment 1 of the present application.

[0020] Figure 2A is a view showing the process of Step 1 in Embodiment 1.

[0021] Figure 2B is a view showing the process of Step 2 in Embodiment 1.

[0022] Figure 3 is a view showing an example of items input to and output from the database in Step 1 of Embodiment 1.

[0023] Figure 4 is a view showing an example of the structure of the database in Embodiment 1.

[0024] Figure 5 is a view showing the step of making the incident angle of the electron beam irradiated onto the sample the same in Embodiment 2.

[0025] Figure 6 is a view showing an example of items input to and output from the database in Embodiment 2.

[0026] Figure 7 is a view showing an example of the structure of the database in Embodiment 2.

[0027] Figure 8 is a view showing an outline of the system of the structure in which the database is provided outside a plurality of charged particle beam devices in Embodiment 3.

[0028] Figure 9 is a view showing an example of the line profile that becomes the reference for matching and an example of the line profile that is set as the object of matching in Embodiment 4. DETAILED DESCRIPTION

[0029] The charged particle beam device of the present application has a database in which analysis values and measured values of parameters related to the device are stored, and uses the database to find the optimum parameters. In the database, analysis values and measured values of parameters of a plurality of items under as many conditions as possible are stored while maintaining the mutual correspondence between the parameters in as wide a range as possible. That is, in the database, the value of an arbitrary one parameter is stored in correspondence with the values of other parameters at the time the value was obtained. When matching is performed, by searching the database for optical conditions that satisfy the target values of the parameters, the optimum parameters of the device can be efficiently found in a short time.

[0030] An embodiment of the charged particle beam device according to the present application will be described below with reference to the drawings. An example of a scanning electron microscope (SEM) will be described below as an example of a charged particle beam device. Further, in the drawings used in the present specification, the same reference numerals are assigned to the same or corresponding constituent elements, and sometimes repeated description thereof will be omitted.

[0031] In the present specification, parameters related to the charged particle beam device are classified into three, optical conditions (first parameters), values related to device performance (second parameters), and information on device structure (third parameters). The optical conditions (first parameters) include an acceleration voltage and a deceleration voltage of the electron beam, an opening angle of the electron beam, a current value of the electron beam, voltages of each electrode, a current value and a voltage value of the lens, a current value and a voltage value of the deflector, an irradiation voltage (voltage of incidence of the electron beam to the sample), and a probe current. The values related to device performance (second parameters) are values of items indicating device performance, including an aberration amount, a line profile, a beam diameter, an angular magnification, a rotation angle, a deflection sensitivity, a deflection amount, a detection rate, and an incidence angle of the electron beam. The information on device structure (third parameters) is an item of information indicating the physical configuration of the constituent elements of the device, including a shape of the lens, a position in the height direction of the lens, a position in the lateral direction of the lens, a tilt angle of the lens, an axis shift amount of the lens, a flatness of the lens, a position in the height direction of the sample (working distance).

[0032] Embodiment 1

[0033] Figure 1 is a diagram indicating the structure of the charged particle beam device of Embodiment 1 of the present application. The charged particle beam device of the present embodiment is provided with an electron gun 1, a first condenser lens 3, a blanker 6, a Faraday cup 7, a second condenser lens 8, an objective lens 9, a deflector 11, a secondary electron detector 13, a control electrode 14, and a height sensor 15. The charged particle beam device of the present embodiment is further provided with the following constituent elements 701-710.

[0034] The electron gun 1 is controlled by an electron gun control section 701, and emits an electron beam 2 as a charged particle beam by an extraction voltage applied between an electron source 101 and an extraction electrode 102 and a thermal energy applied to the electron source 101. The electron beam 2 is accelerated by an acceleration voltage Vo applied to an acceleration electrode 103, and is irradiated to a sample 10 from the electron gun 1.

[0035] The first condenser lens 3 is controlled by a lens control section 702. The electron beam 2 is condensed by the first condenser lens 3, and is reduced by the aperture 4 to become the electron probe 5.

[0036] The blanker 6 is controlled by a blanker control section 703, and deflects the electron probe 5 as necessary.

[0037] A Faraday cup 7 detects a probe current Ip irradiated to the sample 10. The probe current Ip is measured by a current measurement section 704.

[0038] The second condenser lens 8 is controlled by a lens control section 705. The objective lens 9 is controlled by a lens control section 707. The electron probe 5 is further condensed by the second condenser lens 8 and focused on the sample 10 by the objective lens 9. At this time, the electron probe 5 is decelerated by a deceleration voltage Vr applied to the sample 10. The deceleration voltage Vr is controlled by a high voltage control section 709.

[0039] The deflector 11 is controlled by a deflection control section 706. The electron probe 5 is scanned on the sample 10 by the deflector 11.

[0040] The secondary electron detector 13 detects a signal, i.e., secondary electrons 12, generated from the sample 10 by irradiation of the electron probe 5. The signal generated from the sample 10 includes reflected electrons.

[0041] The control electrode 14 is disposed in the vicinity of the objective lens 9, controlled by an electrode control section 710, and controls the trajectory of the secondary electrons 12 by a control voltage applied thereto. The control electrode 14 is applied with a voltage higher than that applied to the sample 10 as necessary to increase the amount of the secondary electrons 12 detected by the secondary electron detector 13, or applied with a voltage lower than that applied to the sample 10 to return the secondary electrons 12 to the sample 10, thereby controlling the amount of charging of the sample 10.

[0042] The height sensor 15 is controlled by a height sensor control section 708 and measures the position in the height direction (working distance) of the sample 10.

[0043] The charged particle beam device of the present embodiment further includes a central control section 801, a manual operation section 900, an operation screen section 903, a result display section 902, and an image processing section 901.

[0044] The central control section 801 is connected to the constituent elements 701-710 and the constituent elements 900-903 and controls the charged particle beam device.

[0045] The manual operation section 900 is an input section for an operator to operate the charged particle beam device via the central control section 801.

[0046] The operation screen section 903 displays information necessary for the operator to operate the charged particle beam device. For example, the operation screen section 903 displays a list of optical conditions.

[0047] The result display section 902 displays information, such as optical conditions, line profiles, etc., calculated by the charged particle beam device of the present embodiment.

[0048] The image processing section 901 obtains an image of the sample 10 from a signal generated from the sample 10 by irradiation with the electron beam 2. In addition, the image processing section 901 performs image processing on an image acquired by the charged particle beam device, calculates an incident angle of the electron beam 2 to the sample 10, or acquires information of the sample 10 such as a line profile.

[0049] The charged particle beam device of the present embodiment further has a self-diagnosis system 501. The self-diagnosis system 501 has an input section 601, a database 604, a learner 605, an output section 606, and a storage section 607.

[0050] The input section 601 inputs information required for the learner 605. For example, the input section 601 inputs a value related to an optical condition (first parameter), a value related to a device performance (second parameter), information about a device structure (third parameter), and a target value (desired value) of the value related to the device performance (second parameter).

[0051] The database 604 stores, for the optical condition (first parameter), the value related to the device performance (second parameter), and the information about the device structure (third parameter), a measurement result (measured value) of the charged particle beam device and an estimated value (analyzed value) as a result of analysis by the learner 605. The database 604 stores a plurality of values for each of a plurality of items of these parameters. The plurality of values of these parameters are stored while maintaining correspondence with each other.

[0052] The learner 605 performs analysis using data stored in the database 604, searches for an optimal value of the optical condition, or estimates a characteristic of the device (information about the device structure (third parameter)). The learner 605 can perform analysis using a pre-imagined information about the device structure (third parameter) and various optical conditions (first parameter), and calculate the value related to the device performance (second parameter).

[0053] The output section 606 outputs the optical condition (first parameter) and the information about the device structure (third parameter) searched by the learner 605 to the central control section 801 and the result display section 902.

[0054] The storage section 607 mainly stores information such as the optical condition (first parameter) and the information about the device structure (third parameter) calculated or searched by the learner 605.

[0055] The database 604 and the learner 605 can be constituted by a computer device provided inside the device, or can be constituted by a computer device provided outside the device and connected to the device through a cable or a network. In addition, the database 604 and the learner 605 can be provided on a cloud.

[0056] The operator selects the optical conditions for inspection from the list of optical conditions displayed on the operation screen section 903, and operates the manual operation section 900 to input the values to the central control section 801, thereby determining the control values of the charged particle beam device. The control values of the charged particle beam device refer to values of parameters for controlling the constituent elements of the device such as the objective lens 9, and include, for example, the optical conditions such as the acceleration voltage Vo, the deceleration voltage Vr, the probe current Ip. If the control values are determined, the charged particle beam device can capture the image of the sample 10 by imaging the sample 10. The operation screen section 903 displays the control values such as the optical conditions stored in the database 604.

[0057] In the charged particle beam device as described above, since the operator selects the optimal optical conditions in accordance with the type of wafer and the pattern forming process, it is necessary to store a large number of optical conditions in the database 604 in advance. However, in order to find the optimal optical conditions including matching, represented by the information on the device structure (third parameter) and the control values of the device, it is necessary to consider the effects of changes in the device structure and the control values on the device, and research is required, and the number of combinations of parameters is large in these researches, and therefore, a long time is taken.

[0058] Therefore, the charged particle beam device of the present embodiment has the self-diagnosis system 501 in order to find the optimal optical conditions including matching, taking into account the characteristics of the device. The charged particle beam device of the present embodiment is able to search for the optimal optical conditions including matching by using the database 604, the learner 605, and the results of measurement of the charged particle beam device.

[0059] Next, the method of finding the optimal optical conditions taking into account the characteristics of the device in the charged particle beam device of the present embodiment will be described. The charged particle beam device of the present embodiment searches for the optimal optical conditions taking into account the characteristics of the device by implementing the following two processes.

[0060] Process 1 is the estimation of the characteristics of each device (information on the device structure (third parameter)) at the time of manufacture and assembly. The charged particle beam device differs in the inter-device structure at the time of manufacture and assembly, and the information on the device structure (third parameter) differs between devices. In process 1, the information on the device structure (third parameter) as the characteristics of each device is estimated.

[0061] In process 2, based on the information on the device structure (third parameter) estimated in process 1, the database 604 is used to search for the optical conditions (first parameter) that satisfy the values (second parameter) related to the performance of the device as the target.

[0062] In the database 604, the results of analysis and experiments (measurement results) of the optical conditions (first parameters) related to the apparatus under as many conditions as possible, the values (second parameters) related to the performance of the apparatus, and the information (third parameters) about the structure of the apparatus are stored. In the database 604, the results of analysis and experiments (measurement results) of the values of as wide a range as possible for each of a plurality of items of these parameters are held in correspondence with each other and stored.

[0063] First, the process 1 is described. In the process 1, the information (third parameters) about the structure of the apparatus for a plurality of items is estimated.

[0064] Figure 2A is a diagram showing the process of the process 1. The process 1 is performed on each component of the charged particle beam apparatus. As an example of the components of the charged particle beam apparatus, Figure 2A The process with respect to the objective lens 9 is mainly shown.

[0065] In S11, the charged particle beam apparatus acquires the current value and the voltage value (optical conditions (first parameters)) acting on the objective lens 9 and the position (working distance) in the height direction of the sample 10 (information (third parameters) about the structure of the apparatus) by the lens control section 707 under the conditions set in the apparatus.

[0066] In S12, the current value and the voltage value acting on the objective lens 9 and the position in the height direction of the sample 10 acquired in S11 are input to the database 604. In the database 604, the values (second parameters) related to the performance of each apparatus and the information (third parameters) about the structure, and the results of analysis under various optical conditions (first parameters) are stored in advance.

[0067] Figure 3 is a diagram showing an example of items input to the database 604 in the process 1 and items output (searched) from the database 604.

[0068] Figure 4 is a diagram showing an example of the structure of the database 604. In the database 604, the values of the optical conditions (first parameters), the values (second parameters) related to the performance of the apparatus, and the information (third parameters) about the structure of the apparatus are stored in correspondence with each other.

[0069] Returning to Figure 2A The process of the process 1 is continued to be described.

[0070] In S13, the learner 605 searches the database 604 for the current value and voltage value of the objective lens 9 at the time of focusing on the position in the height direction of the sample 10 acquired in Sll (optical conditions (first parameter)) and the position in the height direction of the objective lens 9 at which the current value and voltage value acquired in Sll are equal (information on device structure (third parameter)). That is, the learner 605 searches the database 604 for the position in the height direction of the objective lens 9 as information on device structure (third parameter) using the optical conditions (first parameter) to perform estimation.

[0071] In S14, the lens control section 707 arbitrarily changes the current value and voltage value (optical conditions (first parameter)) acting on the objective lens 9.

[0072] In S15, the device measures and acquires values related to device performance (second parameter) such as the amount of aberration, beam diameter, angular magnification, rotation angle, and deflection sensitivity after changing the current value and voltage value of the objective lens 9.

[0073] In S16, the current value and voltage value of the objective lens 9 (optical conditions (first parameter)) changed in S14 and the values related to device performance (second parameter) measured in S15 are input to the database 604.

[0074] In S17, the learner 605 searches and finds the information on device structure (third parameter) corresponding to the optical conditions (first parameter) input in S16 from the database 604. In S17, the learner 605 searches the database 604 for the information on device structure (third parameter) such as the tilt angle of the objective lens 9, the axis offset amount, the flatness ratio, and the like using the optical conditions (first parameter) to perform estimation.

[0075] In S18, the learner 605 stores the information on device structure (third parameter) estimated for the objective lens 9 in the storage section 607.

[0076] The learner 605 estimates the information on device structure (third parameter) for the constituent components of the charged particle beam device such as the first condenser lens 3, the second condenser lens 8, and the deflector 11 in the same steps as for the objective lens 9 and stores the information on device structure (third parameter) in the storage section 607. That is, for the constituent components other than the objective lens 9, the control values (for example, the current value and voltage value and the like of the optical conditions (first parameter)) acting thereon are also changed, and the changed control values and the measured values related to device performance (second parameter) are input to the database 604. The learner 605 estimates the information on device structure (third parameter) for each of the constituent components of the charged particle beam device and stores the estimated information on device structure (third parameter) in the storage section 607.

[0077] Next, process 2 will be described. In process 2, the information on the device structure (third parameter) estimated and stored in the storage section 607 in process 1 is used to search for the optimum optical conditions (first parameter) of the plurality of items.

[0078] Figure 2B is a diagram showing the processing of process 2.

[0079] In S21, the input section 601 acquires the information on the device structure (third parameter) of the plurality of items stored in the storage section 607. Also, the input section 601 acquires the target values (desired values) of the values related to the device performance (second parameter) of the plurality of items input by the operator operating the manual operation section 900. The target values of the values related to the device performance (second parameter) can also use the values in the device that becomes the reference for matching.

[0080] In S22, the input section 601 inputs the information on the device structure (third parameter) and the target values of the values related to the device performance (second parameter) acquired in S21 to the database 604.

[0081] In S23, the learner 605 searches and calculates the optical conditions (first parameter) of the plurality of items that satisfy the target values of the values related to the device performance (second parameter) acquired by the input section 601 in S21 from the database 604. The learner 605 searches the optical conditions (first parameter) that provide the target values of the values related to the device performance (second parameter) acquired by the input section 601 from the database 604 under the conditions of the information on the device structure (third parameter) acquired by the input section 601 in S21, or the optical conditions (first parameter) that provide values closest to the target values of the values related to the device performance (second parameter).

[0082] In S24, the output section 606 outputs the optical conditions (first parameter) searched by the learner 605 using the database 604 in S23 to the result display section 902.

[0083] In S25, the device sets the optical conditions (first parameter) searched in S23 as the optical conditions of the device, and measures the values related to the device performance (second parameter) such as the aberration amount, the deflection amount, and the detection rate.

[0084] In S26, the learner 605 determines whether the measured values related to the device performance (second parameter) satisfy the target values. In the case where the measured values related to the device performance (second parameter) satisfy the target values, S27 is entered, and in the case where the measured values do not satisfy the target values, S28 is entered.

[0085] In S27, since the measured value related to the performance of the apparatus (second parameter) satisfies the target value, the learner 605 stores the optical condition (first parameter) searched for in S23 as a new optical condition in the storage section 607.

[0086] In S28, since the measured value related to the performance of the apparatus (second parameter) does not satisfy the target value, the learner 605 stores the measured value related to the performance of the apparatus (second parameter) and the optical condition (first parameter) at the time when the value related to the performance of the apparatus (second parameter) was obtained in the database 604 in correspondence with each other. Then, returning to S23, the learner 605 searches for and obtains again the optical condition (first parameter) that satisfies the target value of the value related to the performance of the apparatus (second parameter) obtained by the input section 601 in S21 from the database 604. The learner 605 repeats the search until the measured value related to the performance of the apparatus (second parameter) satisfies the target value.

[0087] In S28, by storing the value related to the performance of the apparatus (second parameter) and the optical condition (first parameter) in the database 604, it is possible to improve the precision with which the learner 605 searches for the optical condition (first parameter) using the database 604, and it is possible to cause the learner 605 to learn. S28 can not necessarily be executed, but it is preferable to be executed in a manner that the learner 605 can search with high precision.

[0088] In the conventional charged particle beam apparatus, the parameters of a plurality of items (information on the structure of the apparatus (third parameter), optical condition (first parameter)) are each changed by one, and the optical condition (first parameter) that satisfies the target value of the values related to the performance of the apparatus (second parameter) of a plurality of items is searched for.

[0089] In the charged particle beam apparatus of the present embodiment, the parameters of a plurality of items (information on the structure of the apparatus (third parameter), optical condition (first parameter)) stored in the database 604 are searched for simultaneously, and thus it is possible to efficiently obtain the optimal optical condition (first parameter) that takes into account the characteristics of the apparatus in a short time.

[0090] Embodiment 2

[0091] In the matching of the apparatus, sometimes the measurement error under different optical conditions is reduced in the same apparatus. Therefore, even under different optical conditions, it is necessary to make the state of the electron beam 2 the same and the value related to the performance of the apparatus (second parameter) the same. In Embodiment 2, as one example thereof, a step of making the incident angle of the electron beam 2 irradiated onto the sample 10 the same in the value related to the performance of the apparatus (second parameter) is explained. In order to make the incident angle of the electron beam 2 the same, the step explained in Embodiment 1 and the step explained below are used.

[0092] The basic structure of the charged particle beam device of the present embodiment is the same as that of the charged particle beam device of Embodiment 1 shown in FIG. 1. Figure 1 The deflection control section 706 controls the deflector 11, and controls the incident angle of the electron beam 2 irradiated to the sample 10.

[0093] Figure 5 is a diagram showing the step of making the incident angle of the electron beam 2 irradiated to the sample 10 the same.

[0094] Figure 6 is a diagram showing an example of the items input to the database 604 and the items output (searched) from the database 604 in the present embodiment.

[0095] Figure 7 is a diagram showing an example of the structure of the database 604 in the present embodiment. In the database 604, the values of the optical conditions (first parameters), the values related to the device performance (second parameters), and the information on the device structure (third parameters) corresponding to each other are stored in correspondence.

[0096] In S51, the operator selects the optical condition to be the reference of matching (hereinafter, referred to as "reference optical condition") from the list of the optical conditions displayed on the operation screen section 903.

[0097] In S52, the charged particle beam device measures and acquires the incident angle, the aberration amount, and the values related to the device performance (second parameters) such as the detection rate under the reference optical condition in the charged particle beam device to be the object of matching (hereinafter, referred to as "matching target device"). At this time, the sample 10 can use an arbitrary sample, but can also use the wafer in which a plurality of polyhedral structures of the pyramid shape are arranged as described in Patent Literature 2.

[0098] In S53, the operator selects the optical condition (first parameter) to be the object of matching from the list of the optical conditions displayed on the operation screen section 903.

[0099] In S54, the values related to the device performance (second parameters) measured in S52 under the reference optical condition are input to the database 604. In addition, the information on the device structure (third parameters) of the matching target device and the values of the optical condition to be the object of matching (the optical condition selected in S53) calculated by the same methods as the procedures 1 and 2 described in Embodiment 1 are input to the database 604.

[0100] In S55, the learner 605 searches the irradiation voltage, the voltage value and the current value of the deflector 11 (optical condition) that provide the values input to the database 604 in S54 from the database 604.

[0101] In S56, the charged particle beam device sets the irradiation voltage, the voltage value, and the current value searched for in S55 as the optical condition, and measures values related to the device performance such as the angle of incidence, the amount of aberration, and the detection rate under the optical condition (second parameters).

[0102] In S57, the values related to the device performance measured in S56 (second parameters) and the values related to the device performance under the reference optical condition measured in S52 (second parameters) are compared. In the case where the values measured in S56 coincide with the values under the reference optical condition, S58 is entered, and in the case where they do not coincide, S59 is entered.

[0103] In S58, since the values related to the device performance measured in S56 (second parameters) coincide with the values related to the device performance under the reference optical condition, the learner 605 stores the values related to the device performance measured in S56 as the values related to the device performance under the optical condition to be matched in the storage section 607.

[0104] In S59, since the values related to the device performance measured in S56 (second parameters) do not coincide with the values related to the device performance under the reference optical condition, the learner 605 stores the values related to the device performance measured in S56 in the database 604. Then, the process returns to S55, and the learner 605 performs the search again. The learner 605 repeatedly performs the search until the values measured in S56 coincide with the values under the reference optical condition.

[0105] In the above embodiment, the step of making the angle of incidence of the electron beam 2 the same even under different optical conditions is explained. In the present application, in order to make the state of the electron beam 2 the same even under different optical conditions, other parameters can be searched for and calculated by the same steps as explained above.

[0106] Embodiment 3

[0107] In the present embodiment, the structure of using the database 604 in a plurality of charged particle beam devices is explained. If the database 604 is provided outside of a plurality of charged particle beam devices, the database 604 can be shared and used in each device, and matching between devices can be easily performed.

[0108] Figure 8 is a diagram showing an outline of a system of the structure of providing the database 604 outside of a plurality of charged particle beam devices. The basic structure of the charged particle beam device of the present embodiment is the same as that of the charged particle beam device of Embodiment 1 shown in Figure 1 except for the database 604.

[0109] InFigure 8 Among them, as the charged particle beam device, two devices A (Al and A2) and one device B are shown. The device A and the device B are charged particle beam devices of different types from each other.

[0110] The database 604 has two kinds of a standard database (DB) 604A and a plurality of device databases (DB) 604B. The standard database 604A is connected to all of the device Al, the device A2, and the device B. The device database 604B is provided with a number corresponding to the charged particle beam device, and one each of the device Al, the device A2, and the device B is connected thereto.

[0111] The device Al can access the standard database 604A and the device database 604B connected to the device Al. The device A2 can access the standard database 604A and the device database 604B connected to the device A2. The device B can access the standard database 604A and the device database 604B connected to the device B.

[0112] The standard database 604A stores the analysis results of the learners 605 of the respective charged particle beam devices with respect to the respective charged particle beam devices. For example, in the standard database 604A, with respect to each of the device Al, the device A2, and the device B, the analysis results of the values related to the device performance (second parameters) performed by the respective learners 605 under various optical conditions (first parameters) are saved together with the optical conditions.

[0113] The device database 604B stores the measurement results in the connected charged particle beam device. For example, in the device database 604B connected to the device Al, the measurement results of the optical conditions (first parameters) of the device Al, the values related to the device performance (second parameters), and the information on the device structure (third parameters) are stored.

[0114] When matching among a plurality of devices is performed, the charged particle beam device as the matching target exchanges data between the standard database 604A and the device database 604B connected thereto, acquires necessary information (for example, the optical conditions, the values related to the device performance, the information on the device structure), and performs matching in accordance with the steps explained in Embodiment 1 and Embodiment 2.

[0115] When the database 604 is configured as in this embodiment, the analysis results stored in the standard database 604A can be shared and used in a plurality of devices. Therefore, the learners 605 can learn with more data, and thus can efficiently perform matching for a plurality of devices in a short time.

[0116] Embodiment 4

[0117] In the present embodiment, the step of matching using a line profile of a value related to the performance of the apparatus (second parameter) is described. As one of the methods of performing matching between apparatuses, there is a method of performing matching using a line profile of a specimen 10 that is captured. The line profile is information obtained from an image in which the specimen 10 is captured. Hereinafter, the steps of the matching method are simply described. The basic structure of the charged particle beam apparatus of the present embodiment is the same as that of the charged particle beam apparatus of Embodiment 1 shown in Figure 1

[0118] Figure 9 is a diagram showing an example of a line profile 50 that is a reference for matching and an example of a line profile 51 that is an object for matching. The line profile 50 that is a reference for matching is a line profile of a specimen 10 obtained by a charged particle beam apparatus that is a reference for matching. The line profile 51 that is an object for matching is a line profile of a specimen 10 obtained by a charged particle beam apparatus that is an object for matching.

[0119] In the charged particle beam apparatus, a difference in the shape of the line profile is one of the causes of mechanical differences. Therefore, it is necessary to search for an optical condition in which the shape of the line profile 51 that is an object for matching coincides with the shape of the line profile 50 that is a reference for matching.

[0120] The analysis or experiment is performed in advance, and the optical condition (first parameter) such as the irradiation voltage, the acceleration voltage, the deceleration voltage, and the current value of the electron beam 2 is changed to capture the specimen 10, and the line profile of the specimen 10 is obtained. The database 604 stores the obtained line profile. In addition, the learner 605 obtains the change in the line profile when the value of the optical condition (first parameter) is changed, and stores the relationship of the changes in the database 604.

[0121] The operator operates the manual operation section 900 to input the optical condition (first parameter) in which the line profile 50 that is a reference for matching is obtained and the optical condition (first parameter) in which the line profile 51 that is an object for matching is obtained to the apparatus. The image processing section 901 obtains the line profile under each optical condition.

[0122] In the self-diagnosis system 501, the obtained line profile, the optical condition (first parameter) in which the line profile 51 that is an object for matching is obtained, and the information (third parameter) about the structure of the apparatus are input to the database 604. The learner 605 searches for the optical condition (first parameter) in which the shape of the line profile 51 coincides with the shape of the line profile 50 that is a reference for matching from the database 604. The result display section 902 displays the searched optical condition, the line profile obtained under the searched optical condition, and the line profile 50.

[0123] ​The operator inputs the optical condition (first parameter) displayed by the result display section 902 to the apparatus, and takes a photograph of the test sample 10 again. The image processing section 901 acquires the line profile of the test sample 10 under the optical condition. The result display section 902 displays the line profile and the line profile 50. The operator compares the line profile displayed by the result display section 902 with the line profile 50.

[0124] In the case where these line profiles coincide with each other, the learner 605 stores the optical condition (first parameter) displayed by the result display section 902 as a new optical condition in the storage section 607.

[0125] In the case where these line profiles do not coincide with each other, the line profile under the optical condition displayed by the result display section 902 is stored in the database 604. The learner 605 searches for the optical condition (first parameter) in which the line profile 51 coincides with the shape of the line profile 50 serving as a reference again.

[0126] In the present embodiment, the database 604 stores the line profile (information constituting the line profile), and performs matching using the line profile obtained from the image of the test sample 10. By the matching, the optical condition (first parameter) in which the line profiles coincide with each other is found.

[0127] Further, in the present application, information other than the line profile obtained from the image of the test sample 10 can be used to perform the matching.

[0128] Further, the present application is not limited to the above-described embodiments, and various modifications can be made. For example, the above-described embodiments are embodiments in which the present application is described in detail for easy understanding, and the present application is not limited to a mode in which all the structures described must be provided. In addition, a part of the structure of an embodiment can be replaced with the structure of another embodiment. In addition, the structure of another embodiment can be added to the structure of an embodiment. In addition, a part of the structure of each embodiment can be deleted, or other structures can be added, replaced.

[0129] Symbol Explanation

[0130] 1…electron gun, 2…electron beam, 3…first condenser lens, 4…aperture, 5…electron probe, 6…erasure device, 7…Faraday cup, 8…second condenser lens, 9…objective lens, 10…sample, 11…deflector, 12…secondary electron, 13…secondary electron detector, 14…control electrode, 15…height sensor, 50…line profile to be matched, 51…line profile to be matched with, 101…electron source, 102…extraction electrode, 103…acceleration electrode, 501…self-diagnosis system, 601…input unit, 604…database, 604A…standard database, 604B…each device database, 605…learner, 606…output unit, 607…storage unit, 701…electron gun control unit, 702…lens control unit, 703…erasure device control unit, 704…current measurement unit, 705…lens control unit, 706…deflection control unit, 707…lens control unit, 708…height sensor control unit, 709…high voltage control unit, 710…electrode control unit, 801…central control unit, 900…manual operation unit, 901…image processing unit, 902…result display unit, 903…operation screen unit, Ip…probe current, Vo…acceleration voltage, Vr…deceleration voltage.

Claims

1. A charged particle beam device, characterized in that, The charged particle beam device includes: An electron gun that irradiates an electron beam onto a sample; An image processing unit that obtains an image of the sample based on a signal generated from the sample by the electron beam; The database stores multiple resolved and measured values, maintaining a correspondence between a first parameter (optical condition), a second parameter (value related to device performance), and a third parameter (information about device structure). as well as The learner searches the database for and finds the first parameter that satisfies the target value of the second parameter. If the second parameter determined by the charged particle beam device using the first parameter searched and obtained from the database does not meet the target value, the learner stores the determined second parameter in the database in correspondence with the obtained first parameter.

2. The charged particle beam device according to claim 1, characterized in that, The learner performs the following processing: Using the first parameter, the third parameter is searched and obtained from the database; and Under the condition of the third parameter obtained by searching and obtaining from the database, the first parameter that satisfies the target value of the second parameter is searched and obtained from the database.

3. The charged particle beam device according to claim 1, characterized in that, The database has a standard database that can be connected to multiple of the charged particle beam devices. The standard database stores the analysis results of the learner for each of the charged particle beam devices.

4. The charged particle beam device according to claim 1, characterized in that, The database is located outside the charged particle beam device.

5. The charged particle beam device according to claim 1, characterized in that, The charged particle beam device includes an operation screen that displays the first parameter stored in the database.

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